The processing of food and food products frequently involves massaging and tumbling operations. These operations are particularly effective with meats such as cured hams, ham products, bacon bellies, corn beef briskets, beef round, roasts, turkey breasts and other poultry products. When applied to meat products which have been injected with or otherwise subjected to curing brine, tumbling and massaging accelerates the curing process while facilitating the distribution of the curing ingredient throughout the meat. The salt-soluble "binding" protein myosin is also extracted during tumbling in brine. Extraction of myosin from a meat product produces a sticky meat surface which increases the moisture absorption and retention characteristics of the meat and enhances product coherency.
Typically, tumbling is carried out by allowing meat products to fall from the upper part, e.g., of a rotating processing drum, or striking the meat products with paddles or baffles, thereby exerting "impact energy" influences on the muscle tissue of the meat. Massaging is a less physically vigorous activity involving the rubbing of meat surfaces against one another or against a smooth surface of a rotating drum to produce "frictional energy". Firm meat, e.g., beef, mutton and turkey, is usually tumbled whereas pork, chicken and other pale, soft meats are massaged.
Various apparatus for tumbling and massaging of meat and other food products have heretofore been devised. These prior art apparatus often employ rotating drums into which the meat products to be processed are inserted. U.S. Pat. No. 4,657,771 assigned to the assignee of the present invention discloses one such rotating drum processing apparatus. The axis of rotation for the drums may be inclined to varying degrees, with paddle or vane structures supplied when tumbling operations are to be carried out and smoother interior drum surfaces employed when more gentle massaging is called for. The curing fluid, e.g., brine, can be added to the drum, the drum sealed and mechanical tumbling or massaging initiated under atmospheric pressure conditions or, alternately, in a vacuum environment.
Temperature control over the food processing operation is another environmental factor of significance. For example, it is known that subjecting meat to lowered temperatures in the region between 32.degree. F. and 34.degree. F. results in a greater release of myosin. Meat and poultry products which are massaged at lower temperatures therefore exhibit improved internal binding of water molecules. The quality of the meat obtained following subsequent cooking operations is higher, leading to less post-cook purge. Reduced processing temperatures also retard bacterial growth in the meat, improving quality control yields and extending the shelf life of the processed product.
Conversely, elevating temperatures during massaging and tumbling operations with some types of meat can assist in dehydrating the meat in preparation for cooking or can actually function to cook the meat products.
Despite the desirability of exerting temperature control over food tumbling and massaging operations, prior art food processing apparatus which perform tumbling and massaging do not have adequate temperature control capabilities. Some work in the area of evaporative cooling of processed foodstuffs is believed to have been done in the past. Evaporative cooling, however, removes significant amounts of water from the foodstuffs undergoing processing, an undesirable consequence for many meat products which impacts deleteriously on further meat processing and cooking steps. Other approaches to temperature control, specifically cooling of the foodstuffs using carbon dioxide gas inside the processing drum or placement of the entire drum inside a cold room, have been attempted with equally unsatisfactory outcomes. In short, there is no prior art system which can rapidly and efficiently chill both the curing fluid and the foodstuff inside a food processing drum to a precisely controlled temperature.
It is therefore an object of the present invention to provide a temperature control system for food processing apparatus.
It is another object of the present invention to provide a control system which can be used to precisely adjust the temperature inside a food processing apparatus of the rotating drum type.
It is yet another object of the present invention to provide a system which circulates a temperature controlling fluid around the interior of a rotating drum food processor in order to adjust the interior temperature of the drum.
It is a further object of the present invention to provide a system which can distribute either a cooling fluid or a heating fluid about the interior of a rotating drum food processing apparatus, whereby the temperature of both the curing fluid and the food products inside the drum can be rapidly and efficiently raised or lowered to a desired point.